IF...

I am confused by the difference of these sentences.

A:If you finish the homework, you could go out with me.
B:If you finished the homework, you could go out with me.

Are they correct in grammar?
If so, would you please tell me the difference?

^^^^^^^^^^^^^^^^

Yes Yoko, they are both grammatically correct. Contextually, there is no difference. By that I mean that a child would realize that either one means,

"Finish your homework and you can go out with me".

We choose [some] historical past tense modals to make the situation sound more tentative, [some] historical present tense modals to make a situation sound more real.

'IF' sentences, the First, Second & Third Conditionals, aren't separated by a gulf, ie. they don't operate in isolation. They operate on a spectrum and in some situations we can choose to use either a "past tense FORM" {expressing greater doubt/more tentativeness/etc} or a "present tense FORM" {expressing a less tenative meaning/less doubt/etc}.

We know that these conditionals don't operate is isolation because we often get mixed conditionals like your sentence A.

Mr Pedantic wrote:
So we have two uses of 'could' here:

i) 'could' = tentative version of 'can' (i.e. the speaker is suggesting a course of action)
ii) 'could' = 'would be able to' (i.e. the finishing of the homework would make a course of action possible)

So contextually, there's a world of difference between them. And the girl in question would know it.

+++++++++++++++++

i) 'could' = tentative version of 'can' (i.e. the speaker is suggesting a course of action)
ii) 'could' = 'would be able to' (i.e. the finishing of the homework would make a course of action possible)

That's right, the speaker is suggesting a course of action. In i), that course of action for the less tentative 'can' means 'will be able to'. In this case it doesn't matter to overall meaning or the result which form is chosen.

You can / You could; You will be able to / You would be able to; they all effectively mean the same thing. They only have nuancial differences.

Little children do of course recognize the nuances contained within language structure because they are grammatical geniuses.

Hello katsudon, MrPedantic, ranchhand, and goldmund

Thanks for your insight!
You've been very helpful.

I'll try to read and write conditional sentences
drawing upon your advice.


A thousand thanks.
Yoko